International development minister Lynne Featherstone said FGM had come to "symbolise the brutal oppression" of women across the world, telling the Liberal Democrat conference in Glasgow it must be eliminated.

FGM would "not have lasted four minutes if boys' willies were being cut off", Ms Featherstone argued.

Liberal Democrat MP Lynne Featherstone has demanded more be done to eliminate FGM

Estimates have suggested another 20,000 girls are at risk of being mutilated in England and Wales.

The ritual cutting of girls' genitals is practised by mainly African, and also some Middle Eastern and Asian communities, who believe it protects the sexual purity of girls. In Somalia, 97% have had their clitorises removed.

No-one in the UK has every been prosecuted under the law which bans FGM.

Ms Featherstone, who started to try to deal with the problem as a Home Office minister before she was moved in last year's reshuffle, said there was now a "real opportunity" to make progress as a number of African countries were introducing new laws banning the practice.

She said: "Of all the terrible things that are done to woman across the world, from the UK right across the world, female genital mutilation has to be a priority because to me it is totemic, it symbolises that brutal oppression of women.

"It's a practice that has been going 4,000 years and, without wishing to be crude about this, quite frankly if it was boys' willies that were being cut off without anaesthetic it wouldn't have lasted four minutes, let alone 4,000 years.

Speaking during a debate on a motion to set out the party's policy to deal with domestic and sexual violence, Ms Featherstone called for men who abuse their partners to no longer be placed on anger management programmes but to take part in specialist "behaviour-change" courses instead.

The motion was passed with an amendment calling for those who send girls abroad to have FGM to be prosecuted.

The Home Office has agreed to fund a new study into the number of women living in the UK who have been "cut", usually abroad, in order to identify girls vulnerable to FGM.